1. The distensibility of the resistance vessels of the skin at the dorsum of the foot was determined in 11 long-term type 1 (insulin-dependent) diabetic patients with nephropathy and retinopathy, nine short-term type 1 diabetic patients without clinical microangiopathy and in nine healthy non-diabetic subjects.
2. Blood flow was measured by the local 133Xexenon washout technique in a vascular bed locally paralysed by the injection of histamine. Blood flow was measured before, during and after a 40 mmHg increase of the vascular transmural pressure, induced by head-up tilt.
3. The mean increase in blood flow during headup tilt was only 24% in diabetic subjects with and 48% in diabetic patients without clinical microangiopathy, compared with 79% in normal non-diabetic subjects (P < 0.0005 and P < 0.05, respectively).
4. An inverse correlation between microvascular distensibility and degree of hyalinosis of the terminal arterioles in biopsies from the skin was demonstrated (r = − 0.57, P < 0.001).
5. Our results suggest that terminal arteriolar hyalinosis reduces the microvascular distensibility and probably increases the minimal vascular resistance, thereby impeding hyperaemic responses.
Abnormal regulation of sympathetic nervous activity and heart rate after oral glucose in Type 1 (insulin-dependent) diabetic patients